Pyrotechnic device



June 14, 1938. M. w. FISCHER PYROTECHNIC DEVICE Filed NOV. 27, 1935 Patented Junei4, 11938 i 2,120,246

UNITED STATES PATENT FEIC` PYROTECHNIC DEVICE Max W. Fischer, Washington, D. C.

Application November 27, 1935, Serial No. 51,814 s claims. I (ci. 1oz-24) (Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) This invention relates to pyrotechnic devices ness. The vents II are closed by a rupturable and, more particularly, to rockets of the type that sealing disc Il that is clamped in place by a are fired from a mortar or a like smooth bore gun nut I 8 screwed on spindle 6 and which has and has among its several objects to provide openings I9 in alignment with the vents Il.

means for preventing the escape laround the A cylindrical member 20 is preferably of metal,

rocket of the, gas of the charge that ejects the is secured Abyvclamping theoverturned edge 2| `rocket from the barrel. A further object is to thereof between the container 8 and flange I 6 utilize the pressure developed by the ejection of base 5, and is of sufficient length to contain the charge to expand a thin metal member to effect pyrotechnic unit consisting of a parachute 22 and 1U the obturation of the gases. Other objects will a charge 23 of combustible material for a flare or 10 appear from the description which follows. the like attached to the parachute. A combust- Invthe drawing: ible sealing disc 24 is disposed over the expulsion Fig. lis a longitudinal axial section of a rocket charge I and against this disc is seated an anernbodying my present invention; nulus 25 of felt or like material'. In the com- 15 Fig. 2 is a section on line 2 2, Fig. 3, showing bustible disc 26 that incluses the lower end of the 15 a ilight-steadying element that may be used 'in charge 23 are plugs 21 of a starter composition connection with various pyrotechnic devices; that will burn with a sufficientlyhigh tempera; Fig. 3 is a diametrical section taken on the ture to insure the ignition of the charge 23, the line 3 3, Fig. 2; and combustion of the plugs 21 being initiated by Fig. 4 is a plan View of the base of the device. fuses 28 which in turn are ignited by expulsion The present invention has in view the improvecharge 'I. When the device is dropped into the ment of that type of pyrotechnic devices that are barrel of the rocket gun, the primer 29 strikes fired by dropping them into the barrel of a the ring pin, is exploded thereby, and ignites` mortar or rocket gun having a firing pin at the the delay train 3l). The hot gases from the declosed end of the barrel, which pin strikes a lay train pass through vents 3l and ignite ejecprimer carriedby the device and so ignites the tion charge I0, and as this charge burns the charge that propels the rocket from the barrel. gases produced thereby pass through the vents However, the rocket must be freely slidable in I2 into channel I3 and expand the thin metal of the barrel, otherwise the friction with the barrel cup I4 tightly' against the barrel The ressureA 3 will so diminish the speed of the rocket as to builds up further and ruptures the disc I1 where- 3'0 prevent firing the primer and when such looseness upon the gases pass through the vents II and of it does obtain there is a great loss of propul- 'openings I9 and eject the rocket from the barsive effort due to escape of the gases of the ejecrel. It is apparent that by thus expanding the tion charge around the rocket. The prevencup I4 before the rupturing of disc I'I the gases tion of such loss of energy is one of theimporof the ejection charge are eiectively prevented 3;, l

tant features of my invention. from escaping around the rocket and their en- 'Ihe base member 5 has a hollow spindle 6 extire energy is used in the propulsion thereof. tending from one face thereof and a cavity to Ihe delay train 30 is so timed that the expulcontvain the expulsion charge 1 in the opposite sion charge 'I will be red when the rocket is at 40 face. Acontai'ner Sis in screw-threaded engagethe highest point of its trajectory-and the ex- 40 ment with the base at 9 and'serves to inclose the pansion of the gases produced thereby will rupejection charge Ill. The container 9 has in its ture 'the disc 24, ignite the fuses 28, and expel closed end an aperture through which the spindle the pyrotechnic unit from the cylinder 20', the 6 extends and also in the closed end it is proclosure 3l being blown out and thus leaving the vided with a plurality of vents II extending parparachute 22 free toopen and support the flare 45 allel to the axis of the device. A plurality of vents resulting frOm the burning Of Charge 23. I2 extend from the ejection charge I0 to a cir- In some cases it is desirable to provide means cumferential channel I3 for a purpose that will steadying the flight of the rocket and such means presently appear. An obturating acup I4 of thin, isV shown in Figs. 2 and 3. Instead of the closure soft metal is disposed around the container 8 3i, I may substitute a cup 32 having tethered to 50 and has an overturned edge I5 that is tightly it and spirally wound in it a tape 33 which is reclamped between the container and the ange I6 tained, until the rocket is fired, by a paper memon base 5 but is apertured in registry With the ber 34 which is attached to the outer end of axially extending vents II; The obturating cup tape 33. When the rocket is red the set back is preferably of copper about 0.03 inch in thickruptures the paper 34 and thereafter when the 55 rocket turns end for end in flight as it will do since the base 5 andparts associated therewith make that end of the device the heavier, the paper 34 and the tape attached thereto will be caught by air currents and the tape caused to unwind and stream behind the rocket so it acts as a vane to steady the flight of the rocket.

Copperizing of the barrel from which the rocket is red, due to friction of the obturating cup against the barrel, may be prevented by coating the outer surface of cup I4 with powdered graphite mixed with clear, thin lacquer and dried thereon. However, any other suitable friction reducing agent may be used instead of that suggested.

The-invention described herein may bemanufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

I claim:

1. In a pyrotechnic device, comprising a base having a-hollow spindle extending therefrom and a cavity in communication with the bore of said spindle, an ejection charge container having a lateral wall and a base with the free edge of said wall secured to the first mentioned base substantially enclosing said spindle, said container having vent holes through its lateral wall and also through its base, and an aperture inits base through which said spindle extends, there being vents in said spindle in communication with said bore and said container, said container having a circumferential channel intersecting the said vent holes through its lateral wall, an obturating cup of thin, soft metal enclosing said container and having its edge overturned and clamped between said container and said base, said cup being radially expansible substantially throughout its length to provide a large area sealing contact with a, barrel through Which the device is being fired, said cup being perforated in registry with the vent holes through the base of the container, a rupturable sealing disc disposed against the base of said obturating cup, a

nut screwed on said spindle against said disc and having vent holes aligned with the vent holes in the base of said container, a primer Seated in the outer end of the bore in said spindle, a combustible dis'c over the said cavity in said base, a felt annulus disposed over the last mentioned disc, a pyrotechnic unit yseatedon said annulus, a@

metal cylinder enclosing said unit and having an edge clamped between said container and said base', a frictionally retained closure for the outer end of said cylinder, an ejection charge in said container, an` expulsion charge in said cavity in said base, and a delay train in the bore of said spindle in contact with said expulsion charge.

2. In a pyrotechnic device, comprising a base having a hollow spindle extending therefrom and a cavity in communication with the bore of sid spindle, an ejection charge container having a lateral wall and a base with the free edge of said wall secured to the first mentioned base substantially enclosing said spindle, said container having vent holes through its lateralwall and also through its base, and an aperture in its base through which said spindle extends, there being vents in said spindle in communication with said bore and said container, said container having a circumferential channel intersecting the said vent holes through its lateral Wall, an obturating cup of thin, soft metal enclosing said container and having its edge overturned and clamped between said container and said base, said cup being perforated in registry with the vent holes through the base of the container, said cup being radially expansible substantially throughout its length to provide a large area sealing contact with a barrel through which the device is being red a rupturable sealing disc' disposed against the base of said obturating cup, a nut screwed on said spindle against said disc and having vent holes aligned with the vent holes in the base of said container, a primer seated in the outer end of the bore in said spindle, a combustible disc over the said cavity in said base, a felt annulus disposed over the last mentioned disc, means for operatively retaining a pyrotechnic unit seated against said annulus,"Y an ejection charge in said container, an expulsion charge in said cavity in said base, and a delay train in the bore in said spindle.

3. In a pyrotechnic device, comprising a base having a cavity in .one face thereof, an expulsion charge therein, means to retain an ejection charge in operative association with said base,

vsaid means being provided with vents to permit escape of gases, resulting from the burningyof 5,

said ejection charge, parallel to the axis of said device and also transversely thereto, a. member disposed-around said means to besubstantially uniformly radially expanded by the said gases escaping transversely to said axis, a rupturable member closing the said vents parallel to saidaxis, a delay train to re said expulsion charge, means to ignite said delay train and said ejection charge, a pyrotechnic unit seated over said expulsion charge, and means to retain said unit so positioned until expelled by said expulsion charge.

4. A pyrotechnic device, comprising means to contain a pyrotechnic unit to be readily separable therefrom, a pyrotechnic unit therein, an explosive charge to expel said unit from said means,.

an ejection charge associated therewith to propel said device from a suitable barrel, means 'to direct a portion of the energy of said ejection charge to propel said device, and obturating means fixed at both ends and enclosing said ejection charge to be substantially uniformly radially expanded by the explosion of said ejection charge to prevent escape of the said propulsive energy around said device.

5. In a pyrotechnic device, comprising. a base member, an ejection chargev associatedathexewith, a container engaged with said base and enclosing said charge, said container having in it vents extending parallel to the axis of.v said device and other vents extending transversely to said axis, and a circumferential channel intersecting said transversely extending vents, a cup of thin,

soft metal enclosing said container and secured thereon, said cup beingy perforated in registry with the said vents parallel to said axis, a rupturable member disposed to close said parallel vents,

and means to retain said rupturable member inwith the said lvents parallel to said axis, a rupturtive position, and a. coating of dry lubricant on the exteriorof said cup.` t

7. A pyrotechnic device, comprising a base member, an ejection charge associated therewith, a container engaged with said base and enclosing said charge. said container being' adapted to direct a portion of the gases of combustion of said charge rearwardly of said device and a portion of said gases tranversely of said device, and elongated obturating means substantially coexte'nsive with said container disposed to' be acted upon by said transversely directed gases to be substantially uniformly radially expanded by said gases portion around said device.

8. A pyrotechnic device to be red from a directing means, comprising means to contain a pyrotechm'c unit to be readily separable therefrom, a pyrotechnic unit therein, a. relatively heavy base and associated parts to contain explosive material secured to ,owend-of-'mr'wi said means. a. cup-sha d-r'mber in the other end of said s d mentioned means, a helically wound tape in said member and attached at vone end to said member, and a closure over said member 'attached to the other end of said' tape, said closure being adapted to be ruptured by the set-back" when said device is fired from said directing means.

` MAX W. FISCHER. 

